CA1079007A

CA1079007A - Compositions and process for cleaning fabrics

Info

Publication number: CA1079007A
Application number: CA268,140A
Authority: CA
Inventors: Dennis Postlethwaite
Original assignee: Unilever PLC
Current assignee: Unilever PLC
Priority date: 1975-12-18
Filing date: 1976-12-17
Publication date: 1980-06-10
Also published as: ZA767500B; FR2335593A1; NL184483B; BE849540A; NL7614001A; ES454217A1; DE2657043C2; ATA923776A; AT362034B; SE7614253L; NO764273L; FI61714B; PT65982B; NO146244B; PT65982A; DK571876A; JPS5520520B2; US4119557A; FI61714C; CH624709A5

Abstract

Abstract of the Disclosure Bleaching compositions comprising a hydrogen peroxide liberating persalt, such as sodiumperborate, and a pre-formed ferric ion complex with a polycarboxyamine-type chelating agent, selected from the group consisting of ethylene diamine tetraacetic acid, nitrilotriacetic acid, diethylene triamine pentaacetic acid, and hydroxyethyl ethylene diamine triacetic acid, and mixtures thereof.
The composition is used for cleaning fabrics.

Description

~079007 This invention relates to bleaching compositions and a process for cleaning fabrics.
Fabric washing compositions comprising at least one surface-active compound of the anionic, noniniC or zwitter-ionic type and a percompound bleaching agent, such as sodium ` perborate, sodium persilicate, sodium percarbonate and sodium perphosphate, are known. The amount of percompound bleaching agent used in such compositions is normally about 5-35% by ~-weight of the total composition.
It is known that many heavy metal ions catalyse the I ~ decomposition of H202 and H202-producing percompounds, such i as sodium perborate. It has also been suggested to use heavy metal salts together with a chelating agent, for -,.
improving the bleaching activity f percompound bleaches.

Not all heavy metals nor all chelating agents on -~
.. ::
combination appeared to be suitable for improving the -bleaching performance of H202-producing percompound bleaches. ~ ~ -Many combinations indeed show no effect or even a worsening effect on the bleaching performance; no proper rule seems, however, to exist by which the effect of metal ion/ --~ : , chelating agent comb1nations on the bleaching performance of peroompound bleaches can be predicted.
Many attempts have been made to select the most suitable metal/chelating agent combination for said 25~ ~ purpose and to correlate bleach-catalysing effect with some physical constants~of the combination, so far without much success. U.S. patent no. 3,156,654 suggested particularly cobalt and copper salts in conjunction with ~ -~079007 pyridine-2-carboxylic acid or pyridine-2,6-dicarboxylic acid, preferably as a preformed complex as being a suitable combination. Further British patents nos. 984,459 and 1,192,524 suggested the use of a copper salt in combination - -with other specific chelating agents, such as methylamino-diacetic acid, aminotriacetic acid, hydroxyethylamino-diacetic acid, ethylene diamine tetraacetic acid, and diethylene triamine pentaacetic acid.
Typical is that previous investigators have focussed , 10 their efforts practically towards the use of non-ferrous metals such as Cobalt and Copper salts. This is probably -understandable from the fact, that all these metals including Cobalt and Copper-ions are known as very power-~` ful H202-decomposition catalysts.
It has now been found that, quite surprisingly, certain pre-formed ferric ion chelate complexes have a pronounced activating effect, which is at least equal to j or even much better than many of the hitherto known specific metal ion/chelating agent combinations on the bleaching performance of hydrogen ~peroxide ar.d persalts, which effect, ¦ unlike that of some other metal ion/chelate systems, is reproducible and consistent~
The effect is quite surprising since not much attention has hitherto been paid to iron as a heavy metal ~-~
catalyst for bleaching, possibly due to opined inferiority to other metals. The effect is furthermore surprising since the effect observed is specific to ferric ion in combination ~- with specific chelating agents.

~" ~ -3-~::, The term "persalt" is used hereto mean a salt which releases hydrogen peroxide in aqueous solution, such as e.g.
the alkali metal perborates, percarbonates, persilicates and perphosphates.
S Accordingly the invention provides a bleaching compo-sition for fabrics comprising a persalt and a pre-formed ferric ion chelate complex.
The invention also provides a process for cleaning fabrics by contact with an aqueous solution of hydrogen peroxide or a persalt and a pre-formed ferric ion chelate complex.
The pre-formed ferric ion chelate complex used in the present invention is formed with a particular group of poly-carboxyamine type chelating agents. The polycarboxyamine type chelating agents used in conjunction with the ferric ion according to the invention are ethylenediaminetetra-, acetate (EDTA), nitrilotriacetate (NTA), diethylene triamine pentaacetic acid (DTPA) and hydroxyethyl ethylene diamine triacetic acid (HEEDTA). For practic~ reasons a complex of ferric ion with ethylenediaminetetraacetic acid ~
is preferred, particularly the one comprising ethylene -diamine tetraacetic acid ferric mono sodium salt.
The complex of the invention can be readily prepared by the simple addition of a water-soluble ferric salt, e.g.
ferric sulphate, to a warm to hot solution of the chelating agent, from which the complex is isolated either by precipitation or crystallisation or by any other known separation technique.
' -.. . . ..

, ~07~0()7 C 540 (R) The above-mentioned EDTA-ferric mono sodium salt can be prepared by the addition of a water-soluble ferric salt, e.g. ferric sulphate, to a hot solution of EDTA (tetra- or ` disodium salt). The pale yellow complex crystallises out of solution and is a stable non-hygroscopic solid, which on analyses appears to have the general formula ~Fe.EDTA.nH20] .Na in which n = 0-2. It has a stability constant of 25.1 at 25C.
As the persalt bleaching agent which is used in the --present invention can be mentioned e.g. sodium perborate tetrahydrate, the best known and most used percompound, as well as other persalts known in the art, such as sodium ~ -perborate monohydrate, sodium percarbonate, sodium per-silicate and sodium perphospates.
15The range within which the ferric~ion chelate complex in solution shows enhancement of the bleaching performance of hydrogen peroxide and persalts begins already at levéls as low as 1 ppm and extends further to above 70 ppm. On observ~ation of a curve plotted for a 15 minute isothermal wash at 90C, the main characteristics thereof are a rapid and pronounced bleach activation on introduotion of the c~omplex~of~the invention into the system, followed by a ; gradual decline of the activation performance on furt-her inorease of~the complex level over the concentration range

2~5 ~studied. The optimum pH for the best bleaching with the ferrio ion ohelate complex is ~etween 8.5 and~lQ.5 preferably between;9 - 10.
A major~advantage of the present invention is that iron 1079~7 is used here, which unlike other heavy metals, such as copper, chromium, nickel and cobalt, is quite a harmless and non-sensitising metal, making the invention attractive for use in all sorts of applications where there is possible skin contact.
The practical value of the present inver.tion is that at the same persalt level in the product an increased bleaching action is achieved, and consequently a certain bleaching level can be achieved by using a lower proportion of the persalt in the composition at the expense of adding only very minor proportions of the complex of the invention.
According to the invention the optimum feasible concentration range for the ferric ion chelate complex in the wash-solution is of the order of 2.5-50 ppm, preferably 5-40 ppm, or expressed in more desirable molar terms, from about 5-135 ~moles/litre, preferably 10-120 ~moles/litre.
¦ Based on the normal dosage of use of 5 g/litre of bleaching, or bleaching and detergent compositions, said range will correspond to about 0.05%-1.0% by weight, pre-ferably from about 0.1% to about 0.8% by weight of the total composition. In admixture with a persalt bleaching agent -the ferric ion chelate complex will be present in an amount of about 0.1-7%, preferably 0.25-5%, by weight of the per-salt.
Thus the invention pertains to a bleaching, or a bleaching and detergent composition comprising essentially from 0% to about 50% by weight of an organic surface-active agent selected from the group consisting of anionic, .

~079007 nonionic, zwitterionic, cationic detergents, and mixtures thereof; from about 5~0 to about 80% by weight of builder salts; from about 5% to about 35% by weight of a persalt bleaching agent; and from about 0.05% to about 1.0% by weight of a pre-formed ferric ion chelate complex.
Preferred are detergent and bleaching compositions which contain from about 5% to about 35% by weight of an organic surface-active agent selected from the group con-sisting of anionic and nonionic detergents, and mixtures thereof; from about 10% to about 60% by weight of water-soluble builder salts, preferably comprising sodium tripolyphosphate; from about 10% to about 25% by weight of a persalt bleaching agent, preferably selected from - the group consisting of alkali metal perborates, alkali metal percarbonates, and mixtures thereof; and from about 0.1% to about 0.8% by weight of a pre-formed ferric ion chelate complex.
~ The pH of the composition of the invention (measured `~ from a 0.5 % solution) should preferably lie within the 1 20 range of about 8.5-10.5, more preferably between 9-10.
In addition thereto, inert salts, such as sodium sulphate, and any of the conventional adjuncts used in I bleaching and detergent compositions, such as fluorescent ! agents, soil suspending agents, e.g. sodium carboxymethyl `i 25 cellulose; alkaline agents, corrosion inhibitors, and ~i other auxiliary agents including enzymes may be present ' in the composition of the invention. - -~ypical anionic detergents are the alkylbenzene sUlphonates 107900'7 having from 8-16 carbon atoms in the alkyl group, e.g. sodium dodecylbenzene sulphonate; the olefin sulphonates having from 10-20 carbon atoms, obtained by reacting an alpha olefin with gaseous diluted sulphur trioxide and hydrolysing the -S resulting product; alkyl sulphates such as tallow alcohol sulphate; and alkali metal salts of long chain fatty acids, such as stearic acid and/or palmitic acid. ~ -Typical water-soluble nonionic detergents are the condensation products of alkyl phenols with ethylene oxide e.g. the reaction product of nonylphenol with 6-30 ethylene oxide units; condensation products of higher fatty alcohols, such as tridecyl alcohol and secondary C10-Cl5 alcohols with ethylene oxide, known under the trade name of "Tergitols'~
supplied by Union Carbide; condensation products of tallow lS alcohol with ethylene oxide; condensation products of fatty ` amide with 8-lS ethylene oxide units and the condensation products of polypropylene glycol with ethylene oxide.
Zwitterionic detergents include derivatives of aliphatic quaternary ammonium, phosphonium and sulphonium compounds in which the aliphatic moieties can be straight chain or branched, and wherein one of the aliphatic substituents ~ -:
contains from 8 to 18 carbon atoms and one contains an anionic water-solubilizing group. -~
Cationic detergents include the quaternary ammonium compounds, e.g. cetyl trimethyl ammonium bromide or chloride; and the fatty alkyl amines.
It is an important feature of the present invention that the ferric ion chelate complex is preformed before it -8- `
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is incorporated in the bleaching, or bleaching and detergent composition, or before addition to the bleaching bath, since only then there will be a maximum benefit achievable.
The compositions of the invention may be presented in any of the known solid forms of bleaching or bleaching and detergent compositions, e.g. as a powder, which term includes also hollow beads such as obtained from spray-dry-ing a slurry, coarse particles, and fine powders; as flakes, as granulates and as tablets.
A preferred form of the composition is a powder which is obtained by the conventional spray-drying technique, where-in the basic detergent ingredients including the pre-formed ferric ion chelate complex is formed into a slurry which is then fed to a spray-drying tower to form a dry free-flowing powder which is collected at the bottom of the tower. Any ' heat-sensitive ingredients can be dry mixed with the spray-l dried powder. Alternatively the pre-formed ferric ion chelate complex may be incorporated by post-addition as a separate in-gredient to the spary-dried base powder.
i 20 As explained above, the composition of the invention on dissolving in water will produce effective concentrations ~ -,~ of the ferric ion chelate complex in the bleaching bath to -, catalyse the bleaching action of the persalt e.g. sodium - -perborate, to a satisfactory extent. ;
Accordingly in a further aspect, the invention pertains ;-to a process for cleaning fabrics by contacting said fabrics with ~; an aqueous solution of hydrogen peroxide or a persalt, which solution contains from about 1-70 ppm, preferably from 2.5-50 ppm, ' ~07~007 of a pre-formed ferric ion chelate complex.
In one more specific embodiment of the invention the process comprises the use of a solution comprising a persalt and 2.5-50 ppm of a ferric ion chelate complex selected from the group of Fe3+/EDTA, Fe /NTA, Fe +/DTPA, Fe3 /HEEDTA
and mixtures thereof, and having a pH of about 8.5-10.5.
A preferable range of complex level is 5-40 ppm; a prefer-able pH range is from about 9-10.
~ It should be appreciated as indicated before that the ; 10 invention is applicable with any of the known percompound bleaching agents, including hydrogen peroxide and percom-pounds which liberate hydrogen peroxide in aqueous solution, such as the alkali metal perborates, percarbonates, persili-cates, perphosphates, etc.
The invention can be applied to bleaching and cleaning baths such as are used for treating textiles, to wash liquors such as are used in commercial and domestic launderings, and to solid bleaching compositions.
In practising the invention the man in the art is of course free to choose any level of the pre-formed complex - :
within the range as defined hereinbefore, as he would think desirable for serving his purpose, but for economic reasons in the majority of cases the lowest level that still brings ~
about the highest activation will be selected for use. `; -The advantages of the invention ane shown in the following illustrative examples:

C 540 (R) Example I
The effect of various Fe3 systems on perborate bleaching using two detergent bases was investigated.
Bleach tests were conducted in clean systems on tea-stained cotton test pieces using deionised water.
The results for given additives are shown in Table I
in which bleaching scores are expressed in terms of conven-tional reflectance increase values (~ R460).
Bleach/washing conditions:
15 min. isothermal wash at 90C.
0.375% detergent base solution + 0.125% sodium perborate.
Fe3 level = 1 ppm (=6.5 ppm pre-formed Fe3 /EDTA complex, when present).
EDTA level = 0.1% and 0.2% (when added separately).
TABLE I
_.................. _ ¦ Addltive Detergent ~ase A ¦ Deter~ ~t R~se ~ ¦

. . .
None 14.8 13.1 ~e + EDTA 15.9 16.8 . ~e3 + 2 EDTA 14.4 _ ~e3 / EDTA 17.6 20.1 complex _ :

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10790~ c 540 (R) Compositions of detergent bases A B
Sodium dodecylbenzene sulphonate 20.6 30.6 Coconut ethanolamide 3.9 4.6 Sodium toluene sulphonate 2.6 Sodium tripolyphosphate 45.2 53.6 Alkaline silicate 14.2 Sodium sulphate 13.7 9.2 Sodium carboxymethylcellulose - 1.5 The results show that there is a definite advantage in the use of the pre-formed Fe3 /EDTA complex over the Fe3 and EDTA added separately.
Example II
.
- This example illustrates the effect of Fe3 /EDTA
complex level on the bleaching performance of sodium per- ~-borate.
Bleach tests were conducted in clean systems on tea-, stained cotton test pieces using deionised water.
,~ The results are shown in Table II, in which bleaching scores are expressed in terms as used in Example I.
' 20 Bleach/washing conditions:
, 15 min isothermal wash at 90C;~heat-up from 20-95C.
Ø375% detergent base solution + 0.125% sodium perborate.
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'~ ~07go~7 c 540 (R) TABLE II
. _ _ Complex level Detergent Base A Detergent Base B

ppm in wt% in Heat-up 20-95C 15 min isothermal soln. product ~ R wash at 90 C
__ _ __ _ 0 0 16.6 16.1 1.3 0.03 _ 18.1 2.6 0.05 _ 19.6

3.9 o.o8 _ 19.7 5.2 0.10 _ 19.7 6.5 0.13 22.0 20.7 13.1 0.26 21.0 21.0 19.5 0.40 20.6 20.1 26.o 0.52 20.6 lq.4 32.5 0.65 20.1 19.3 Example III
This example illustrates the effect of Fe3 /NTA com-plex, Cu /EDTA complex and Co /EDTA complex on the bleach-ing performance of sodium perborate.
Bleach tests were conducted in clean systems on tea-,stained cotton test pieces using deionised water.
Bleach/washing conditions: --0.375% detergent base Al 0.125% sodium perborate 15 min isothermal washes at 75C and 90C.
The results are shown in Table III.

.

: 1079007 c 540 (R) TABLE III
. _ Complex Level ppm 75C 90C
in soln. ~ R ~
. .
Fe3 /NTA 0 6.9 13-9 21.8 9.6 15.1 43.6 8.2 12.3 2+ _ _ ~u ~EDTA ~ 0 ¦ _ ¦ 11.6 . 31.1 _ 13.3 , 62.2 _ 15.0 . . , "o'+/EDTA 0 7-7 14.7 6.7 7.8 14.4 13.3 8-5 14.4 33.3 8.1 11.5 . 66.6 8.6 10.7 ~ .
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:~0790~7 C 540 (R) note: 4.4 ppm Fe3 /NTA- 6.2 ppm Cu2 /EDTA - 6.7 ppm Co2+/
EDTA = 1 ppm metal ion equivalent.
These results clearly show the non-effectiveness of copper/EDTA and cobalt/EDTA complexes to catalyse bleaching by sodium perborate, in contrast to the positive effects observed with a ferric ion chelate complex of the invention.
E~ample IV
This Example illustrates the effect of Fe3 /EDTA com-plex on commercial products containing sodium perborate.
Three commercial perborated detergent powders were B obtained, UX Surf, UK biological OMO~and UK Tide, and their perborate levels were determined by iodometric titration.
The following perborate levels were found: ~ -UK Surf - 22.3%
UK Biological OMO - 22.8~
UK Tide - 18.8%
Bleach tests (heat-up wash cycle 20-95C) conducted with these powders at 0.5% product concentration and at dif-~ ferent Fe3+/EDTA levels on tea-stained cotton test cloths - 20 using deionised water gave resuits as shown in Table IV
below.
.' , ~ TABLE IV
.

Complex level UK Surf Bio OMO Tide ppm soln. _ _ _ ~; ~ R ~ R ~ R
`~ 25 _ __ 0 19.9 17.8 15.6 _ . .. _. ... _ . ._ . .

~ denokS trc~de ~ar~

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. - .. . . . .. . -1079~ C 540 (R) Complex level UK Surf Bio OMO I Tide ppm soln. ~ R ~ R I ~R

:~ . _ :' 6.5 24.5 22.3 19.4 13.1 22.5 21.7 18.6 19.5 22.8 - 21.1 19.0 26.0 21.8 20.5 18.2 32.8 21.4 20.7 18.3 .. .
The results again demonstrate a pronounced activating effect for systems concerning Fe3 /EDTA complèx of the inven-tion.
Example V
In order to assess perborate savings which may be realised with Fe3 /EDTA catalysed bleaching, experiments 15~ were performed at different perborate levels. Two series of experiments were conducted. The first series of experi-ments directly compared the effect of a constant level of Fe3 /EDTA complex at decreasing perborate levels with the performance of perborate alone.
20 ; ~ First serles of experiments 15 min. isothermal washes at 90C
0~.375%~dstergent base~A + sodium pe~borate 6.5 ppm Fe ~/EDTA complex (- 1 ppm Fe3 on solution -; 0.13% complex on base powder) 25~ The recults are given in the following Table V1 ~ - . . . . . . : . . . . . . .. . .

10790~ c 540 (R) TABLE Vl Perborate level ~ R
% on product 13 11.7 16 12.7 19 14.2 22 15.5-16.4 _ 25 _ _ _ _ _ 15.1 _ ~ Control experiment without complex.
These results when plotted graphically will show that the 25% perborate product without complex is equivalent to one containing about 21% perborate + 0.13% ferric ion/EDTA
complex. This suggests that use of the complex may save approximately 4% of sodium perborate.
A second series of experiments was conducted, compar-ing a system outside the invention with the system of the invention using the following bleach/washing conditions:
15 min. isothermal washes at 90C using deionised . water.
0.375% detergent base A
Fe3+= 1 ppm EDTA = 5.5 ppm.
Fe3 /EDTA complex = 6.5 ppm Th~e results are given in the following Table V2 -below.

~ ~ -- '-'~
~ ' C 540 (R) . I
Additive Perborate levels ~-- 10 % ~ 15 ~ ¦ 2 0 None 9.2 10.2 ¦ 12.5 15.0 Fe +EDTA 8.4 10.1 13.5 15.9 Fe3 /EDTA 9.4 complex ll.B 15.2 ~ 1~ 6 These results again confirm the superiority of the pI ~e-formed Fe3 /EDTA complex over its separate components.
Graphical treatment of the data shows that a product containing 19.5% perborate + 0.13% complex is equivalent to a 25% perborate only product, giving a potential perborate saving in this instance of approximately 5.5%.
Example VI
The following Example gives a further illlustration of the effectiveness of ferric ion complexes according to the invention for activating the bleach performance of H202 at 90 C. Figures are also given for some cobalt and copper complexes, for comparison.
Bleach tests were conducted using an isothermal wash at 90 C ~or 15 minutes,as the standard conditions. The complexes assessed were prepared by simple aqueous mixing in stoichiometric ratio of metal ion and chelating agent, 25~ followed by isolation, either by precipitation or . :::

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C 540 (R) ~07900~
crystallisation.
All evaluations were conducted in solutions of an EDTA-free detergent base A of Example I and a standard complex level such that its level of metal ion in solution was 1 ppm, was adopted.
To 250 ml of base solution (0.375%), thermostatted at 0C, were added 1.0 ml of standard metal ion complex solution, four tea-stained test pieces (5 x 5 cm), and finally sodium perborate (0.313 g) in that order. After 15 minutes the test pieces were withdrawn and subsequently, after rinsing and drying, assessed reflectometrically at R 460. Control runs were conducted in the absence of metal ion complex.
The results are summarised in the following Table VI.
TABLE VI
_ Complex Bleach 1) Activa~3On Complex increment Ratio ~quivalent ~(~R) A.R. Level3) _ C.E.L. (%) Fe3+/NTA + 2.9 1.19 21 -Fe /DTPA + 2.4 - -1 16 22 Fe3+/HEEDTA + 2.3 1 15 22 Fe3 /EDTA + 2.7 1.14 22 Cu2+/NTA + 2.8 1.15 22 Cu /DTPA - 0.3 0.98 26 Cu2 /EDTA - 1.0 0.93 Co /EDTA - 0.3 0.9~ 26 Co -/DPA - 0.5 0.92 27 - Co2+/pA5) -10.0 0.47 53 - -. _._ -1 9- :

~ ~ .

- . - . - . .. :

~079007 C 540 (R) )Bleach increment ~(~R): The reflectance difference b~tween clothes bleached in the presence and absence of complex, i.e.
~ (~R) = i~RC - ~Rp where ~Rc = Reflectance increase from perborate + complex ~Rp = Reflectance increase from perborate alone.
Activation ratio (A.R.): The ratio of reflectance increase in the presence of complex to that in its absence, i.e.
A-R. = i~RC / ~Rp , Com~lex equivalent level (C.E.L.): Level of perborate required in a system with the complex for its performance to match that of 25% perborate alone; i.e.
~ C.E.L. ~ 25/A.R.
,~ 15 4)Pyridine-2,6-dicarboxylic acid.
5)Pyridine-2-carboxylic acid.
The above results show that under the conditions tested ,~ all the Fe3 complexes examined increased the bleach performance; the Cu2+ complexes and Co2+ complexes tested generally deactivated bleach periformance, except for Cu2 /
NTA. Apparently they act principally as efficacious H202 decomposition catalysts.
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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A bleaching, or bleaching and detergent composition.
comprising essentially from 0% to 50% by weight of an or-ganic surface-active agent selected from the group con-sisting of anionic, nonionic, zwitterionic and cationic detergents, and mixtures thereof; from 5% to 80% by weight of builder salts; from 5% to 35% by weight of a persalt;
and from about 0.05% to about 1.0% by weight of a pre-formed ferric ion chelate complex, said complex being a complex of ferric ion with ethylene diamine tetraacetic acid (EDTA), nitrilotriacetic acid (NTA), diethylene tri-amine pentaacetic acid (DTPA), or hydroxyethyl ethylene diamine triacetic acid (HEEDTA).

2. A composition according to claim 1, containing essentia1ly from 5% to 35% by weight of an organic surface-active agent selected from the group consisting of anionic and nonionic detergents, and mixtures thereof;
from 10% to 60% by weight of water-soluble builder salts;
from 10% to 25% by weight of a persalt, and from about 0.1% to about 0.8% by weight of said pre-formed ferric ion chelate complex.

3. A composition according to claim 1, having a pH, measured from a 0.5% solution of 8.5-10.5

4. A composition according to claim 3, wherein the pH
is from 9-10.

5. A composition according to claim 1, wherein said ferric ion chelate complex is present in an amount of about 0.1-7.0% by weight of the persalt.

6. A composition according to claim 5, wherein said complex is present in an amount of 0.25-5% by weight of the persalt.

7. A process for cleaning fabrics by contacting said fabrics with an aqueous solution of a composition comprising essentially from 0% to 50% by weight of an organic surface-active agent selected from the group consisting of anionic, nonionic, zwitterionic and cationic detergents, and mixtures thereof; from 5% to 80% by weight of builder salts; from 5% to 35% by weight of a persalt; and from about 0.05 to about 1.0% by weight of a pre-formed ferric ion chelate com-plex, said complex being a complex of ferric ion with ethylene diamine tetraacetic acid (EDTA), nitrilotriacetic acid (NTA), diethylene triamine pentaacetic acid (DTPA), or hydroxyethyl ethylene diamine triacetic acid (HEEDTA).

8. A process according to claim 7, wherein the com-position comprises essentially from 5% to 35% by weight of an organic surface-active agent selected from the group consisting of anionic and nonionic detergents, and mixtures thereof;
from 10% to 60% by weight of water-soluble builder salts;
from 10% to 25% by weight of a persalt, and from about 0.1% to about 0.8% by weight of said pre-formed ferric ion chelate complex.

9. A process for cleaning fabrics by contacting said fabrics with an aqueous solution comprising hydrogen peroxide or a hydrogen peroxide liberating persalt and about 1-70 ppm of a pre-formed complex, selected from the group consisting of ferric ion complexes with ethylene diamine tetraacetic acid, nitrilotriacetic acid, diethylene triamine pentaacetic acid, or with hydroxyethyl ethylene diamine pentaacetic acid, and mixtures thereof.

10. A process according to claim 9, wherein said solu-tion has a pH of about 8.5-10.5 and said pre-formed ferric ion chelate complex is present in an amount of 2.5-50 ppm.

11. A process according to claim 10, wherein said pre-formed ferric ion chelate complex is present at a level of 5-40 ppm.

12. A process according to claim 10, wherein said pH
of the solution is from about 9-10.